Abstract: The enzymolysis degree of protein from soybean by three enzymes respectively was researched under different conditions.The result showed that Enzyme B had the best enzymolysis effect. The optimum conditions of enzymolysis was : 55℃, 0.1mg/ml and 4h. Then soybean milk was hydrolyzed by Enzyme B at the optimum enzymolysis conditions. The product was mixed with fresh milk with three different proportions respectively, and the optimum fermentation conditions were studied. The results showed that when the product was mixed with fresh milk at the proportion of 1:1, 4% amount of L.bulgaricus and Str.thermophilus(1:1) were inoculated in the mixture, while 8% sucrose and 0.04% concentrated vanilla were added in and the time of primary fermentation was 4h. Thus the soy milk yoghurt had the highest comprehensive evaluation, and its applicational potentialityw as great.

Key words: soybean milk, enzymolysis, soy milk yoghurt, fermentation